摘要：The resolution and quality of the depth map captured by depth cameras are limited due to sensor hardware limitations, which becomes a roadblock for further computer vision applications. In order to solve this problem, we propose a new method to enhance low-resolution depth maps using high-resolution color images. The structural-aware term is introduced because of the availability of structural information in color images and the assumption of identical structural features within local neighborhoods of color images and depth images captured from the same scene. We integrate the structural-aware term with color similarity and depth similarity within local neighborhoods to design a local weighting filter based on structural features. To use non-local self-similarity of images, the local weighting filter is combined with the concept of non-local means, and then a non-local weighting filter based on structural features is designed. Some experimental results show that super-resolution depth image can be reconstructed well by the process of the non-local filter and the local filter based on structural features. The proposed method can reconstruct much better high-resolution depth images compared with previously reported methods.

摘要：设计了Mg-2.7Nd-0.2Zn-0.4Zr(质量分数,%)镁合金作为可降解生物医用材料。对固溶处理后的铸锭进行了热挤压处理,然后对挤压棒分别进行了时效处理、固溶处理及固溶+时效处理。利用光学显微镜和扫描电镜观察了合金的组织,测试了合金的室温力学性能,采用析氢和失重法测试了合金在模拟体液中的降解行为,用扫描电镜观察了降解产物形貌及洗去降解产物后的形貌。结果表明:固溶处理后合金的晶粒明显长大,固溶处理显著提高挤压态合金的伸长率,但降低了合金的强度,而时效处理可提高合金的强度,降低合金的伸长率;热处理可降低合金的屈强比。体外降解实验结果表明:固溶处理使合金的降解速率稍微加快,而时效处理则能稍微减慢合金的降解速率。

摘要：A biosensor device, built from graphene nanoribbons （GNRs） with nanopores, was designed and studied by first- principles quantum transport simulation. We have demonstrated the intrinsic transport properties of the device and the effect of different nucleobases on device properties when they are located in the nanopores of GNRs. It was found that the device＇s current changes remarkably with the species of nucleobases, which originates from their different chemical compositions and coupling strengths with GNRs. In addition, our first-principles results clearly reveal that the distinguished ability of a device＇s current depends on the position of the pore to some extent. These results may present a new way to read off the nucleobases sequence of a single-stranded DNA （ssDNA） molecule by such GNRs-based device with designed nanopores

摘要：According to previous studies,stiffened shells with convex hyperbolic generatrix shape are less sensitive to *** this study,the effects of generatrix shape on the performances of elastic and plastic buckling in stiffened shells are ***,a more general description of generatrix shape is proposed,which can simply be expressed as a convex B-spline curve(controlled by four key points).An optimization framework of stiffened shells with a convex B-spline generatrix is established,with optimization objective being measured in terms of nominal collapse load,which can be expressed as a weighted sum of geometrically imperfect *** effectiveness of the proposed framework is demonstrated by a detailed comparison of the optimum designs for the B-spline and hyperbolic generatrix *** decrease of imperfection sensitivity allows for a significant weight saving,which is particularly important in the development of future heavy-lift launch vehicles.

摘要：生物材料支架的精确设计和制造是骨组织工程系统研究的基础。生物材料支架应该同时满足大孔隙率和与骨组织匹配的力学性能要求。这两个目标相互制约,大的孔隙率会降低其力学性能。利用拓扑优化的方法,在体积分数的约束下,寻求刚度最大的最优材料分布微结构。建立算法,得到了不同体积分数的2D和3D最优微结构,并提取3D拓扑优化的结果,然后将其转化为STL格式的CAD模型文件。微结构在三维方向整列成支架结构,通过选区激光熔化方法制造30%(体积分数)的Ti支架样品。从SEM图像看出,支架样品的结构和孔径与CAD模型基本一致,500μm微结构单元的平均孔径为231μm。复杂形状金属生物材料支架的精确制造证实了选区激光熔化技术在金属生物医学材料制造中的可行性。

摘要：在深部煤矿开采中,巷道往往处于高地应力和强动力扰动的动静载叠加应力环境。由动静载叠加诱发的围岩严重变形破坏甚至灾变失稳现象屡见不鲜,严重威胁煤矿的安全高效开采。因此,对动静载叠加作用下巷道围岩变形破坏规律的研究具有非常重要的理论价值和工程意义。本文以数值模拟中非线性动力计算为手段,研究了不同初始应力场及不同动载条件对巷道围岩的影响,获得了动静载叠加作用下巷道围岩变形破坏规律。结果表明:水平应力、垂直应力及动力扰动都与巷道围岩塑性破坏呈正相关关系,其中动力扰动对其影响最为明显。在相同应力条件下,巷道顶板和两帮的变形量及塑性破坏范围始终大于底板。水平应力对巷道变形量的影响比垂直应力更加强烈。所以,对于高应力环境中的矿井需加强地应力测试,并在巷道设计时充分考虑巷道布置及开采顺序。对于受动力扰动强烈的巷道,要求支护构件(锚杆、锚索等)在受到一定动力扰动后仍能保持其有效性。这一研究结果有助于进一步了解动静载叠加作用下深部巷道围岩变形破坏规律,并可为相似地质条件下巷道支护设计及优化提供相应的指导。

摘要：由于航改三轴燃气轮的排气温度很低,传统的联合循环技术并不适用于三轴燃气轮机。湿空气透平(HAT)循环不需要高温余热,因此,为航改燃气轮机提供了一种新的选择。然而由于单轴燃气轮机结构更加简单,现有的HAT循环试验电站都是基于单轴燃气轮机设计的,而将航改燃气轮机改造为HAT循环依然缺乏充分的研究。本文提出了一种基于航改燃气轮机的HAT循环模型,详细介绍了基于模块化建模的饱和器、燃气轮机和换热器的建模方法,并通过对国产某航改三轴燃气轮机的仿真验证了该方法的准确性。仿真结果表明,在不改变燃气轮机尺寸和运行特性的前提下,直接转变为HAT循环后,由于注入水的缘故,系统无法达到原有的额定透平进口温度。但是,当HAT循环运行在额定功率时,系统效率依然可以提高0.16%。此外,仿真结果还表明,当考虑燃气轮机改型后,HAT循环效率的提升非常显著。文章结果对基于多轴燃气轮机,特别是航改燃气轮机的HAT循环设计与分析提供了参考。

摘要：离子插层是提高Ti_(3)C_(2)TxMXene电化学性能的有效方法之一.然而,不同的插层离子对MXene的结构和电化学性能的影响是否相同这一问题尚不清楚.本文系统研究了Li+、Na+、K+、Cs+、Zn2+、Mg2+、SO_(4)2-和OH-等一系列离子插层后的MXene的结构特征和电化学性能.研究结果表明,插层离子的半径、电荷数和化学特性对插层效果都会产生影响.在所研究的插层剂中,由离子半径最大的一价阳离子Cs+和具有强碱性的阴离子OH-组成的插层剂CsOH对MXene具有较好的插层效果.插层后的MXene层间距增大,层间容纳了大量游离水,Ti的价态升高,片层表面有利于氧化还原反应的含O官能团增多,这都大大促进了电解液离子H+的扩散与存储.由此制备的电极的质量比电容大幅度提高,为原始MXene电极的7倍多,而且经过20,000次充放电循环后电容保持率未发生下降.本文为具有高电容性能的MXene和MXene基复合电极的合理设计和制备提供了指导.

摘要：实际状态下的土体一般是非饱和的。基于极限分析理论,本文开展了稳定渗流作用下加筋土加固非饱和土边坡的稳定性分析。借助有效应力法对基质吸力引起的表观黏聚力功率进行了计算,从边坡稳定的能量平衡方程中推导出了维持边坡稳定的所需黏聚力和稳定性系数,并编制了最优化程序来捕捉稳定性系数最优解。文章进行对比分析以验证本文所采用方法的有效性,其后采用参数响应分析的手段以探讨土体类型、渗流速率、加固强度以及土体基质吸力对边坡稳定性的影响。为方便初步设计使用,文章最后给出了一系列的稳定性系数最优解。

摘要：近年来,纳米尺度上范德华材料中声子极化激元的研究因在纳米光子学中的潜在应用而受到广泛关注.这些材料具有亚衍射分辨成像和传感的独特能力,因而成为纳米光子学领域新技术开发的热门途径.尽管声子极化激元材料的研究取得了很多进展,但由于这些材料的绝缘特性,其在实现声子极化激元的动态可逆操纵方面仍然存在挑战.最新研究发现,借助VO_(2)薄膜,可以实现α-MoO_(3)中各向异性声子极化激元的可逆操纵.VO_(2)薄膜是一种近室温相变材料,因其相变前后绝缘态和金属态之间介电性能的巨大变化受到广泛关注.最新的一项研究展示了精心构建的α-MoO_(3)/VO_(2)异质结构,改变温度调控VO_(2)薄膜的介电性能,能够调谐中红外波段极化激元的传播.这些结果展示了一种在纳米尺度上控制光能流动的有效方法,并为集成平面亚衍射激元器件的设计和制造提供了指导.